Automatic safety-clutch.



E. H. RAMELLI. AUTOMATIC SAFETY CLUTCH. APPLICATION man APR. s. 1915.

1 1 69,1 93 Patented Jim. 25,` 1916.

i To all Iwhom t mag/concern:

y 1,1easraet.v

EMILE H. RAMELLI, OF NEW ORLEANS, LOUISIANA.

AUTOMATIC SAFETY-CLUTCH.

` Be it known that I, EMILE H. RAMELLn a citizenof the United States, residing at New Orleans, in the parish of Orleans and State of Louisiana, have invented certain new and useful Improvements in Automatic SafetyvClutches, of which the following is a specification. A

My invention relates to automatic safety clutches for use in driving the tool operated by a vdental engine, or generally where 1t 1s desired to rotatably connect one member to another so that the drive will yield when a given torque is exceeded, or when the tool or driven member of the clutch meets a greater resistancethan normal.

One embodiment of my invention is illus- `trated in the accompanying drawings in Figure l is a side view of my device. Fig. 2 is a longitudinal sectional view through the casing and showing the clutch. Fig. 3 designates detailed views of the separate parts of the clutch.

. In the drawings in which like reference characters designate the same part in the different views, E and D indicate a casing l in which the clutch members' are housed. As

displacement.

xdriven by a flexible shaft, such shown the two members are connected by a threaded joint S, 'and the reduced bore of the vmember D isy axially spaced from the bore of member E, thereby forming an an-` nular groove P. At the other end, casing vmember E is counterbored and internally threaded'as, at R,

and between the threaded portion'and the smaller bore, a flange H is formed. y j

The member C is formed with a peripheral fiange G which seats in the groove P. This member is rotatable in the casing and the flange and groove hold it from axial One end of member C is reduced andv has the extension C projecting axially outside of the casing.. This extension C is adapted to be connected toand as is used in dental engines. At the other end member C is formed with a plurality of concave recesses C. These recesses are shown as semispherical and are equally spaced on a circle concentric with the axis of member C.y

A member A is also rotatably mounted in Specieati'onof Letters Patent.

Application led April 8, 1915. Serial N o. 20,082.

. piece is constrained to Patented J an. 25, 1916.

the casing. This member is adapted to be located between the recessed end of member C and the flange H of the casing. It is provided at one end with a plurality of convex projections, preferably semi-spherical, adapted to seat in the recesses in member C. The member is hollow for the greater part of its length and has telescoped in the hollow portion, the cylindrical piece A. This e rotate with member but can move axially relative to the same, by means of the piny and slot connection M and K. The other end of piece A is adapted to be connected to means for transmittin itsrotation to the tool held in the tool holder,

tering projections and recesses A and C,

rotationis ypositively transmitted to piece -A thereby driving the tool or whatever may be connected to A. If this tool or driven device meets an obstruction or greater resistance than normal, the greater torque required to drive the same will tend to rotate member C relative to member A. vexprojections will then act as cams, forcing the member A away from member C, against the force of spring B. Member C will continue to rotate, and member. A will remain stationary, -until the obstruction is removed. Spring B will then cause the reengagement of the clutch member A and C and the drive will be resumed.

My device is of especial advantage in dental engines, for driving the tool. Due to the yielding drive connection, vdamage to the patients mouth or operators hands will be prevented, for instance when the hand piece clogs; or stones in the hand piece catch -between teeth; or burs or wheels catch in the rubber dam. Having already described my invention, I claim:-

A clutch adapted to yield when overloaded, comprising a casing, a rotatable member The con-` held against axial movement by the easing,-

a second member mounted for rotatable and axial movement in the casing, Lyielding means interposed between the casing and-the second member for. forcing said second member into engagement with saidrst member,

` the contacting portions of said members being 'provided with coperating send-spherical projections and recesses.

March 12 1915. t

l EMILE H. RAMELLI. Witnesses:

BEN. F. MOSES, H. E. BELDEN. 

